### Chapter #8 :Waves and Sound : Short Q/A / C.R.Q's

Q. If a pendulum is vibrated at a deep well .What will be the effect on the Time Period?
Ans. As we know that g decreases with the depth.
g’=g (1-d/ Re 2)
and the time period of the pendulum is
T=2π√ l/g
So according to the formula if the value of the g decreases the time period will increase
Then if a pendulum is vibrated at a deep well its time period will be grater than on earth.

Q. A wire hangs from a dark high tower so that the upper end is not visible. How can we determine the length of the wire?
Ans. First we tied a point mass with this string and then make it vibrate. The time period of this pendulum can be noticed. Now a/c to formula
L=gT/4 π2
By knowing the value of g, the time period of vibration the length of wire can be calculated.

Q. Is it possible for two identical waves traveling in the same direction along a string to give rise to a stationary wave?
Ans. No . A standing wave, also known as a stationary wave, is a wave that remains in a constant position. This phenomenon can occur because the medium is moving in the opposite direction to the wave, or it can arise in a stationary medium as a result of interference between two waves traveling in opposite directions.

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